Delerium is a side project of Bill Leeb of the industrial band Front Line Assembly. Over the years Leeb has had several different partners (Balch, Fulber, Peterson) and they have used many different vocalists. Originally the music was mainly ambient industrial electronic instrumentals, but the music has evolved to sound more like commercial dance. Their biggest hit came when the track "Silence," featuring vocals from Sara McLachlan, was remixed by Airscape and DJ Tiësto.